Javascript textfield value focus on
Environment: Please use IE for testing it
Requirement: I have an alert message which checks if user enters a value less than 8 digit - user wont be able to move to next field....he should remain on same field.
Problem: Everything is fine with the functionality except one thing - when user enters any value in a textfield less than 8 digits he gets his foucs back in such a manner than the cursor moves to the first letter of the entered value whereas it should go back to the last letter of the entered valued.
Code:
<html>
<body>
<script>
function checkField(field) {
if (field.value.length < 8) {
// Toggle the active element's blur off and back on after the next blur
var active = document.activeElement;
if (active && active !== field) {
var blur = active.o开发者_JAVA技巧nblur || function(){};
active.onblur = function(){ active.onblur = blur };
}
field.focus();
alert("cannot be less than 8 digits");
}
}
</script>
<input type="text" id="test1" onblur='return checkField(this);'>
<br/>
<input type="text" id="test2" onblur='return checkField(this);'>
</tr>
</table>
</body>
</html>
It's a hack, but this works - add an onfocus listener to replace the value with itself, and IE will behave by putting the cursor at the end - onfocus="this.value = this.value;":
Used like this:
<input id="test1" type="text" value="whatever" onblur="return checkField(this);" onfocus="this.value = this.value;" />
If you ever plan to migrate to JQuery (which I recommend), check out this plugin:
// jQuery plugin: PutCursorAtEnd 1.0
// http://plugins.jquery.com/project/PutCursorAtEnd
// by teedyay
//
// Puts the cursor at the end of a textbox/ textarea
// codesnippet: 691e18b1-f4f9-41b4-8fe8-bc8ee51b48d4
(function($)
{
jQuery.fn.putCursorAtEnd = function()
{
return this.each(function()
{
$(this).focus()
// If this function exists...
if (this.setSelectionRange)
{
// ... then use it
// (Doesn't work in IE)
// Double the length because Opera is inconsistent about whether a carriage return is one character or two. Sigh.
var len = $(this).val().length * 2;
this.setSelectionRange(len, len);
}
else
{
// ... otherwise replace the contents with itself
// (Doesn't work in Google Chrome)
$(this).val($(this).val());
}
// Scroll to the bottom, in case we're in a tall textarea
// (Necessary for Firefox and Google Chrome)
this.scrollTop = 999999;
});
};
})(jQuery);
加载中,请稍侯......
精彩评论